Power out of thin air - it's no magic trick

What is the role of wind energy in Green Power Switch?

Initially wind will provide TVA with about 2 megawatts of capacity, but plans are for its share of total green power generation to increase over time.  The production of wind energy creates no air pollution and, if the turbines are sited properly, has minimal environmental impact.  There are currently no wind-energy programs in the Southeast.  TVA and the public power distributors of TVA electricity are introducing this clean technology to the Tennessee Valley.

How is wind energy generated?

Modern wind machines consist of a tower, a turbine and switchgear that are mounted at the top of the tower and housed in a casing called a nacelle, and the blades attached to the turbine.  Generally, the higher the tower, the better the access to wind.  Wind turbines use moving air to produce power by transferring the wind's momentum to the rotor blades and localizing that energy in a single rotating shaft.  The resulting power can be used in many ways; modern turbines convert it into electricity.

How much electricity will the wind turbines produce?

TVA has installed three turbines on Buffalo Mountain in Anderson County, Tennessee.  Each has a generating capacity of 660 kilowatts.  Together, these three turbines produce some 6 million kilowatt-hours per year -- enough to serve more than 400 typical Valley households.

Do wind turbines produce electricity all the time?

No, but when the turbines aren't operating, other resources will continue to supply power as reliably as ever.  Although wind speed varies according to the time of day, season, height above ground, and terrain, proper siting in a breezy location away from large obstructions will enhance a wind turbine's performance.

How are wind sites selected?

The turbines must be situated where the wind is relatively steady and strong.  Windy sites in environmentally sensitive areas will be excluded.   For cost-control reasons, it's helpful to have access to transmission or distribution lines nearby, and access by road is needed for construction and maintenance.

Will the turning rotor blades harm birds?

TVA will study potential wind sites to make sure that they aren't located on bird migration routes and that endangered species don't inhabit or frequently visit them.  Careful site selection will ensure that there is no significant hazard to birds.

Are the wind turbines noisy?

Modern wind turbines have become very quiet.  At distances of more than 650 feet, the swishing sound of the rotor blades is usually completely masked by the natural noise of wind blowing the leaves of trees or shrubs.   The turbine sites will be distant enough from neighbors so that people won't hear any sound at all unless they're standing close to the towers.

Will the turbines interfere with radio and TV signals?

No.  In fact, some turbines even double as communications towers for cellular phone transmitters, among other things.  The turbine blades are made not of metal but of glass-reinforced epoxy (a material similar to fiberglass), and the turbines are equipped with asynchronous (brushless) generators that don't create any electrical disturbance.  For these reasons, the Green Power Switch turbines will cause no electro-magnetic interference and won't disrupt radio or television signals.

How does the cost of wind energy compare to that of traditional electricity?

The technology to convert wind energy to electricity is constantly improving, but electricity produced by wind power still costs several times more than that produced by common sources like coal.  A typical coal-fired generating unit currently produces electricity for a little more than a penny per kilowatt-hour.   The cost of producing electricity using wind to power a turbine ranges between six cents and a little more than 11 cents per kilowatt-hour.